On THE PITHOPHORACE. 15 
spore in its lower end instead of the upper. Instances of this proceed- 
ing I have found in P. kewensis nob., but particularly in P. Cleveana 
nob. Two cases belonging to this category I have represented pl. 4, 
fig. 3 and pl. 3, fig. 8. In the former case, the cell marked me has 
formed first a normal apical spore s, and afterwards an accessorial basal 
spore, sb. The cell just below has also formed a spore, s, in is top; 
thus this one and the basal spore of the upper cell are made to lie 
immediately beside each other, thus forming a pair of seeming twin 
spores. In the latter case, a lower cell has formed two apical spores, 
s’, s” (but which have received only an incomplete parting wall between 
them), whilst the upper cell has formed an accessorial basal spore sb; 
therefore, three spores are here made to lie beside each other, thus form- 
ing a group of seeming triple spores. 
In P. Cleveana nob. the formation of basal spores besides or 
instead. of apical is not at all uncommon. Especially it often happens 
in specimens where no rhizoid has been developed, that the very lowest 
cell of the thallus, brought forth immediately by the germinated spore, 
forms a spore in its basal part (pl. 2, fig. 13 sqb, and pl. 4, fig. 12 sgb). A con- 
sequence of this is the remarkable circumstance, that the spore formed in this 
manner has quite the same place as the original mother spore of that 
plant, and that it even possesses, except at its upper end, exactly the 
same cell-membrane as the mother spore of the plant. This piece of 
membrane will consequently, according to the nature of the germination 
(see »Germination and Increase»), have belonged to three different imdi- 
viduals in succession, viz. 1:0 the one which has formed the spore which 
has, by its germination, given existence to, for instance, the specimen 
represented pl. 2, fig. 13; 2:0 the individual represented by that figure; 
and 3:0 the specimen which the basal spore will form in future, when 
germinating. If it comes to pass (as it probably does sometimes), that 
one specimen after another, without forming a rhizoid, forms a spore 
at the lower end of the plant, the same piece of cell-membrane will 
enter, as a living part, in a whole series of individuals. This circum- 
stance has seemed to me the more remarkable, because it does not exist 
in any other pluricellular plant, as far as I know. 
Only in P. kewensis nob. I have had opportunity to make obser- 
vations on the order in which the spores are formed. Generally it is 
basipetal, 1. e. the top cell in the principal filament or in a branch first 
forms a spore, then the cell just below forms one, and so on in a down- 
ward direction; pl. 2, fig. 5 and fig. 3, 4 sf. Deviations from this order 
